All of the following code is written in Python.
Data is just a dictionary, where the keys are user tokens.
The value for each key is another dictionary, where the keys are the URLs.
I could use a set instead of a dictionary for the URLs, but finding a matching
value in a dictionary is O(1) as opposed to a set, which is O(n). This also
would allow us in the future to add more data to each URL if we wanted to.
E.G. data = {'john': {'google.com': {'potential_future_bool': True}, 'cnn.com': {}}, 'aaron': {'reddit.com': {}}}